Stir together spices and salt. Mix in olive oil and cilantro. Use a sharp knife to make shallow slashes about 1 1/2 inches apart into the fish skin; transfer to a large dish and rub both sides with spice mixture. Refrigerate for 30 minutes to 2 hours.
Preheat a clean, lightly oiled grill to high heat. Place fish, flesh-side down, on hot grill. Do not move for 3 to 5 minutes, or until fish is opaque. Flip using two spatulas. Cook until fish flakes slightly when pressed, about 5 to 7 minutes more.
Transfer fish fillet to a plate. Set aside to cool slightly. Place on a serving platter, shred fillet with fork into bite-size pieces, and garnish platter with lime wedges and cilantro sprigs. Serve immediately, or within 1 hour at room temperature.